Scientists will be designing and mass-producing medical nanorobots from carbon feedstock some decades from now, so as to directly manipulate biochemistry to cure and prevent disease, wear and tear, and ultimately aging itself - but we'll have to get the whole molecular manufacturing technology base sorted out for that. Earlier than this, it seems likely that the first medical nanorobots (well, microrobots in this case) will be highly modified or even completely artificial cells. Why ignore the working blueprint that's right in front of you, after all? Via EurekAlert!: "Our proposal is to use naturally available molecules to create pseudo-cell factories where we create a super artificial cell capable of targeting and treating whatever is ailing the body. The human cell is like a bustling metropolis, and we aim to tap the energy and diversity of the processes in a human cell to help the body essentially heal itself. ... Understanding both the nature of a cell as an independent unit and its role in the life processes of larger organisms is crucial in our quest to duplicate the molecular units which form the building blocks of the cell and its parts. We see this development of artificial cells as a building block for a variety of new and exciting therapeutic approaches."